Transforming an unfinished basement into a habitable zone is a smart way to establish extra square footage in your home – especially if you’ve exhausted the opportunities to extend above ground.
From spacious living areas, playrooms and home offices, to specialist rooms including home gyms, movie theatres and wine storage, the opportunities for expansion are endless.
However, remodelling your basement comes with a host of additional considerations that don’t necessarily apply to construction work above grade level.
Ventilation, waterproofing and ensuring a plentiful supply of natural light are a few of the typical challenges you’re likely to face during your project.
Other potential hurdles include obtaining the relevant permits to carry out construction, electrical and plumbing work.
Here, we lay out the facts you need to carry out a successful basement remodel.
How much does it cost to finish a basement?
The outlay for basement remodel or finishing project is largely determined by the space you’re starting out with.
'It really depends on the amount of clean-up work required; for example, the relocation of existing utilities and things like the addition of a bathroom or kitchenette, says Christopher Tucker, Principal/Owner at MODE4 Architecture , a design practice based in Alexandria, Virginia.
If your existing basement is unfinished, it’s likely that you’re working with a space that’s completely open. Putting in partition walls to zone off bedrooms and bathrooms is an addition that will drive the price up.
Jobs that involve moving the plumbing or incorporating additional structural elements, such as digging down to create more height, are likely to add to overall costs, too.
The cost of specialty rooms is another key consideration. Incorporating a movie theatre, for instance, will require custom AV work and potentially extra sound insulation. It’s important to consider all these factors from the outset so you can get a realistic budget plan drawn up.
'Our smaller basement remodels would cost $75,000 to $100,000, or about $200 per sq ft,' says Christopher. Larger remodels are likely to cost $200,000 and above. When planning out your budget, it’s important to allocate between 5% and 10% as a contingency in case any unforeseen problems crop up along the way.
One way to keep a lid on spending is to take on some of the work yourself, once the construction portion of the project is out of the way. Jobs such as painting, decorating and laying down flooring aren’t beyond the realms of capability for confident DIYers.
Scouring local salvage yards and antique centers for recycled fixtures and furnishings is another way to claw back on costs.
'Where possible, bring in a builder early in the process. It’s a good way to maintain your budget without forfeiting great design solutions,' says Christopher.
'Once you have established a design direction, obtain pricing from builders as a way to check the design against your budget.'
Where do you start when finishing a basement?
Your first step is to decide exactly what functions the new subterranean level should perform.
You can prioritize this list of features by dividing it into ‘must have’ and ‘nice to have’ categories. Taking this approach will also help you keep a firm grip on budget as the project progresses.
'It’s important to be honest with yourself at this stage,' says Liz Caan, founder and principal at Liz Caan & Co., a Massachusetts-based design firm. 'If your basement has a separate entrance, consider the uses and the flexibility this can provide. Maybe a guest suite would be nice, an au pair area, a home office, or a media gaming room? It’s also a good idea to maximize storage in the basement so it feels pulled together and not overly cluttered.'
Once you’ve established your priorities for the remodel, it’s time to track down an architect or designer who understands your vision for the space. Ask around friends, neighbors or colleagues who have recently had any work done to see if they can provide recommendations.
Remember, it’s not just about selecting the designer who has the shiniest portfolio of projects, either. You need to track down a professional who you can communicate with effectively throughout the course of the project - personality can therefore be an important factor in your decision.
The next step is finding a reliable contractor to handle the construction side of the project. Your architect may have some recommendations for reliable firms with plenty of experience working on basement remodels and finishing schemes.
It’s a smart move to source quotes from multiple firms (three to five) before settling on one company – and always be weary if quotes are lacking in detail, or one is significantly cheaper than the others.
Again, getting recommendations from friends or colleagues who have worked with a builder first-hand is a good way to find a reliable firm.
Another option is to go to a specialist remodel company who offer a one-stop-shop service for design, construction, project management and finishing. Having one point of contact throughout the build can take some of the stress out of the process, as it means you’ll be dealing with the same team of professionals from start to finish.
Your design essentials
Regardless of the intended use of your revamped basement, it’s important to create a space that integrates seamlessly with the rest of the house – you don’t want the lower level to feel cut off.
'When remodelling an existing basement, I try to make it feel as important as the rest of the home,' says Liz Caan. 'I prefer nice finishes like plaster ceilings and walls, a wood or stone floor, matching interior doors and a trim molding. I usually use recessed lights as ceiling height can be an issue.'
Introducing natural light into the basement is often one of the key challenges designers face. 'Add new windows to bring in as much natural light as possible,' says Sean Barnett, owner and principal architect at Portland-based Polymath Studio Architecture. 'This is the most effective way to make your basement feel like it’s no longer a basement, but rather a comfortable, inviting part of your home.'
If installing new windows isn’t a possibility, sunpipes can be fitted to channel natural light down into the space. Double height spaces that connect the ground floor to the basement can be another way of opening the space and allowing sunshine to flood in.
'One of the simplest and most cost-effective ways to try and introduce natural light is from the floor above,' says Daniel Adeshile, director of London-based Ade Architecture. 'Can a stairwell void be created to bring light down alongside the access stair, for instance?'
Walk-on rooflights are another solution that allow light to penetrate down to the lower ground level of the home. 'If possible, creating an external lightwell can bring natural light and ventilation into the space,' adds Daniel.
Is finishing a basement worth it?
If you plan on staying in the same property for years to come, finishing your basement to create a bespoke space has the potential to transform your lifestyle.
'I am a firm believer that it’s worth it,' says Liz. 'It’s usually a significant amount of square footage of extra living space, which can truly add value and quality of life in a modest size home.'
Of course, before embarking on your remodel, it’s important to weigh up the pros, cons and potential challenges the project will involve.
'The client, contractor and designer must all be involved when it comes to determining if the overall gain will be worth the cost,' says Lyn Williams, owner of Lyn’s Design Style. 'However, a finished basement adds square footage to a home and allows additional space for a family to live and play in their home – both of which add value.'
It’s also worth bearing in mind that the pandemic has caused a shift in how many of us spend time at home. 'More of us are working and learning at home, to it’s great to have the extra space to spread out,' says Lyn.
'Of course, we enjoy spending time with family – but when we’re with them as much as we have been lately, a basement can provide valuable extra space.'
What is the best flooring to install in a basement?
Flooring has the potential to take up a significant portion of your budget for fixtures and finishes, so it’s important to specify a practical solution that looks great and will stand the test of time.
'I’m a big fan or porcelain tiles, where I can layer rugs over the top of the surface,' says Liz Caan. 'You can have tile that looks like natural wood or metal. Even Belgian bluestone is beautiful. Plus, if you do happen to get water ingress in the basement, the floors will be unharmed.'
If you already have a concrete floor in your basement, an economical way to finish it would be to add a coat of paint. Layering rugs on top of the painted surface would help you to achieve a more unique aesthetic.
How much does it cost to install a bathroom in a basement?
If you plan to incorporate a bedroom or guest annex in the basement, it makes sense to add a bathroom for convenience and ease of access.
'I usually recommend a full bath in the basement so you can shower after a workout or wash the dog in the basement, for example,' continues Liz.
Of course, the installation of this zone will require extra electrical and plumbing work and will therefore drive up overall project costs.
'The average cost to add a bathroom to a basement would be around $10,000 to $15,000,' says Lyn. 'This can vary based on accessibility to existing plumbing, condition of the basement, sewer lines and the finishes you select.'
Based on the other functions your new basement will perform, the addition of a bathroom is something to discuss with your designer during the initial planning stage of the project.
Your builder will then be able to put together projected costs for the bathroom so you can factor it into your budget from the start, allowing you to weigh up whether the additional outlay is worth it.
Remember, if you do decide to invest in a bathroom, you’ll need to adhere to the stipulations laid out by the building code. The National Kitchen and Bath Association also publishes guidelines to help designers and homeowners create bathrooms that are practical and safe, offering further advice on how to plan a bathroom that balances function and form effectively.
Though following this second set of parameters is not a legal requirement for your project, the directions are extremely helpful when it comes to planning a safe bathroom that’s enjoyable to use.
A few of the legal requirements you’ll need to follow include guidelines relating to ceiling height, floor space around fixtures and shower size.
Plus, as a minimum, your bathroom will either require a window measuring at least 3 sq ft or a mechanical ventilation system that conducts 50 cubic ft of air per minute outside.
Do I need permits?
Barring cosmetic projects such as painting your home or laying flooring, most home renovation schemes require a permit – including basements.
'It can vary by jurisdiction, but typically you do need a permit to convert an unfinished basement into living space,' says Sean from Polymath Studio.
Every county has its own set of zoning and development laws, so it’s important to check the local building code and permitting requirements for your area before forging ahead with any work in the basement.
Even if you aren’t making any big structural changes to the basement, such as putting in new walls, electrical jobs such as introducing new wiring or adding circuits will require a permit.
Thinking of adding a bathroom? That’ll require a permit, too, as your plumber will need to run a new plumbing supply and drain line.
If you’re still not sure, a phone call to your local permitting office should give you a good idea of whether a permit is needed.
Before your permit is issued, the project will be assessed by a local inspection officer who checks that your scheme is up to code with local construction standards. If it ticks all the necessary boxes, obtaining the necessary permit should be fairly straightforward.
Basement ideas – Inspiration to create your dream space underground
1. Create a spacious new family room
Seattle-based Best Practice Architecture transformed the basement of this 1912 home into a bright and spacious family area. As part of the remodel, most of the walls were painted white to enhance the airy feeling of the space. Portions of exposed brick wall and the exposed overhead timber ceiling add warmth and texture to the space.
2. Bring natural light to the basement
The remodel of the lower level in the same property has created a spacious family room (see image 1), as well as a bathroom, guest room and an additional home office. Three large windows with window wells were fitted to ensure the space benefits from plenty of natural light. Ainslie-Davis Construction worked with Best Practice Architecture to complete this remodel.
3. Introduce a light-filled playroom for the kids
Prior to renovations carried out by VFA Architecture + Design, the basement in this Toronto home was mainly used for storage purposes. The space was given a complete overhaul to create a light-filled playroom. The rear yard was stepped to create a sunken courtyard. The lower grade allowed for larger windows, channeling more natural light into the basement.
4. Have some fun with a new games room
This basement renovation by Maximilian Huxley Construction restored the lower level of the 1903 home from two separate suits into one shared family space. The project was respectful of the home’s 1903 origins, and has incorporated reclaimed wood floors, countertops, shelving, stair treads and paneling. Exposed steel beams and masonry elements give the space on industrial feel.
5. Introduce a new wine cellar
In this basement renovation by Seattle-based Hoedemaker Pfeiffer, the long neglected cold storage space beneath the porch of the house was re-purposed and transformed to a contemporary wine room. Built-in joinery has been incorporated to maximize every inch of space.
6. Extend under...and out
London-based Granit Architects put together the design for this kitchen-diner basement extension. A glazed double height space ensures the space is filled with natural light.
7. Bring in a spacious new bathroom
This master bathroom was added to the lower level of this Freedman’s Cottage home in Austin, Texas. The original property was extended significantly as part of the remodel, by Webber + Studio. The bathroom is filled with light thanks to the installation of floor to ceiling glazing to the rear of the property.
8. Work from home in comfort
Beige & Bleu planned the design for this basement finishing project in Boston. The space caters for a family of teenage girls, providing a space for them to study and a lounge area, separate from the rest of the house.
9. Go deeper for more ceiling height
Charles Cunniffe Architects dropped the lower levels of this home by two feet to increase ceiling heights in the basement. The remodel transformed the mechanical and crawl space into a spacious family room with a bar, billiards and game room and a glazed wine store.
Now you're armed with the essentials on how to remodel and finish a basement, you'll be able to tackle your own project head on.
Hello! I’m Rebecca, and I freelance for Homes & Gardens. I contribute a range of articles to the magazine, from design-focused features to real life case studies.
After starting my journalism career at a luxury property magazine in Bangkok, I re-located to London where I started out as a sub-editor and features writer. I later became the features editor of a popular self-build and renovation magazine, where I delved into the world of structural systems, eco tech and smart homes.
I went freelance in 2017 to pursue my dream of becoming a yoga teacher, but I still write for numerous titles in the homes and interiors sector.
My background is in self-build and renovation, so I’m happy to chat about a plethora of topics, from oak frames and kit houses, to glazing innovations and cladding.
My dream is to build a contemporary glazed extension to the rear of a traditional Victorian property, and then fill it with furniture from Oliver Bonas, Made.com and Swoon Editions. After visiting an array of spectacular homes across the country, I can’t wait to install underfloor heating in my own house! In my own home, I have cultivated a Japandi style, with a mix of warm Scandinavian tones and textures complemented by Japanese, Korean and Chinese accessories.
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